The overall goal of the new Core C is to provide resources, expertise, and training for RMTSC investigators to characterize the chemosensory capabilities and responsiveness of their model rodents. These include phenotypic assessment of transgenic and knockout mice, as well as organisms with experimentally induced taste and olfactory deficits, including localized delivery of pharmacological agents. The need for an assessment core has arisen because the numbers of gene-targeted and transgenic mice produced and/or utilized by established and new RMTSC core investigators has increased dramatically since the last funding period. Further, several new lines are being developed that will be utilized by multiple RMTSC investigators. These model organisms will require functional validation, both electrophysiological and behavioral. Electrophysiology core services include assistance with chorda tympani and glossopharyngeal taste nerve recording, to assess taste function in anterior and posterior lingual fields, and EOG recording, to assess function of the olfactory epithelium and olfactory nerve conduction. Behavioral assessment facilities include training and expertise in the design and execution of behavioral testing for both taste and olfactory function. These services include assistance with design and analysis of brief access taste tests using the Davis Rig llckometer, long-term 2-bottle preference tests, and olfactory function using the olfactometer. In addition to providing services for established investigators. Core C will aid new investigators who do not have the equipment or expertise to perform these assessments on their own. Further, having central core facilities will enhance collaborations among RMTSC investigators, and bring new investigators into the chemosensory field. It is not the intention of this core to perform all these studies for the participating laboratories, but rather to facilitate the capabilities of the participating laboratories to gain the requisite expertise.